Lymphangiogenesis in Classical Hodgkin Lymphoma - Preliminary Study with Clinicopathological Correlations.

A role for lymphangiogenesis in metastatic breast and prostate cancers has been suggested recently. The relevance of lymphangiogenesis in cancer as a rule, and more specifically in classical Hodgkin lymphoma, is poorly understood in comparison with that of angiogenesis. In a preliminary (pilot) study we have investigated the role of lymphatic vessels growth in 19 cases of classical Hodgkin lymphoma stained with the D2-40 (podoplanin) antibody. In each case, three lymphatic vessels hot spots were scrutinized twice. Of the 57 hot spots thus identified, we chose 15 at random for photography, microvessel counting and image analysis. We determined the mean perimeter, surface area, major axis length and complexity factor for each hot spot and correlated them with clinical and biological features of classical Hodgkin lymphoma. No correlations were found with clinical features. No associations were noted with the standard immuno-markers of classical Hodgkin lymphoma. However, significant inverse correlations were shown with pRb, BAX and IκB-α expression. The mean lymphatic major axis length was inversely correlated with the complexity factor. Last, we carried out an additional clinicopathological correlation of the expression of pRb, BAX and IκB-α in a cohort of classical Hodgkin lymphoma patients previously published.

Adherence of Hodgkin's disease-derived cell lines to the various lymph node compartments.

This adherence study was performed to clarify the trafficking of Hodgkin-Reed-Sternberg (HRS) cells in Hodgkin's disease (HD) and thus try to unravel the peculiar pathways of dissemination in the early stages of this malignant neoplasm. Using non-neoplastic human necropsy or biopsy lymph node as well as tonsillar tissue sections, we have studied the adherence of the KMH-2 and L-428 HD-derived cell lines and have compared it to that of peripheral blood lymphocytes (PBLs). In necropsy lymph nodes, cell lines predominantly adhered to sinuses and paracortex, whilst adhered PBLs were distributed more widely. In biopsy lymph nodes, adhesion to high endothelial venules (HEVs) was rarely observed, whilst cell lines were found to adhere to sinuses. Inhibition by EDTA pretreatment affected adherence to HEVs as well as to sinuses and paracortex to a similar degree. Our findings point to the possible importance of the lymph node sinuses and paracortex in relation to homing of the HRS cells and their dissemination during the early stages of HD. The results suggest a significant primary role of the extracellular matrix of the paracortex and sinuses in the homing of HRS cells, with the HEVs of only secondary importance.

Selectins and anti-CD15 (Lewis x/a) antibodies transmit activation signals in Hodgkin's lymphoma-derived cell lines.

OBJECTIVE: The CD15 (Lewis x) cell surface oligosaccharide moiety is expressed in a variety of normal and tumor cells and recognized by selectins. The detection of CD15 on malignant Hodgkin-Reed-Sternberg (HRS) cells serves as a diagnostic marker of Hodgkin's lymphoma (HL). Retrospective studies suggest that the expression of nonsialylated CD15 molecules on HRS cells has a positive prognostic value while presence of sialylated CD15 may correlate with a poor outcome. However, the relevance of the CD15 antigen expression to the pathobiology of the disease is not clear. In this work, we studied the contribution of CD15 to cell adhesion and the activation of signaling cascades in two HL-derived cell lines, KMH-2 and L428. METHODS: Immobilized anti-CD15 monoclonal antibodies and recombinant E- and P-selectins were used to activate KMH-2 and L428 cells. Immunoblotting, immunoprecipitation, and the electrophoretic mobility shift assay were performed to detect tyrosine phosphorylation of c-Cbl, c-Jun nuclear translocation, and AP-1 DNA binding. RESULTS: Treatment of cells with antibodies against the sialylated and nonsialylated forms of CD15, or with immobilized selectins, induced changes in cell morphology. Tyrosine phosphorylation of c-Cbl, together with tyrosine phosphorylation of multiple protein substrates, was also induced. In addition, binding of the CD15 molecules induced nuclear translocation of c-Jun and an increase in AP-1 DNA binding activity. CONCLUSIONS: We suggest that CD15 has a dual physiological role, both as an adhesion molecule recognized by selectins and as a regulatory molecule upstream to specific intracellular signaling cascades with implications to the pathogenesis of HL.

Hodgkin lymphoma cell lines bind to platelets. Incubation with platelets induces CD15 and P-selectin dependent adhesion of the cell lines to Human Umbilical Vein Endothelial cells (HUVEC).

Hodgkin's lymphoma is believed to spread in an orderly fashion within the lymphatic compartment. In a minority of cases, after reaching the spleen, the neoplasm disseminates, reminiscent of metastasis. In the spleen, the Hodgkin-Reed-Sternberg tumor cells come across platelets in the blood vessels and mainly in the splenic red pulp. Based on this knowledge, we investigated the possibility of platelets inducing cell adhesion in Hodgkin's lymphoma cell lines. We showed that L428 and KMH-2 cells strongly adhere to thrombin-activated platelets. Cell adhesion to platelets is partially dependent on CD15 antigens (Lewis(X)), mainly sialyl-CD15, and P-selectin. KMH-2, as compared to L428 cells, showed increased binding due to its differential high expression of the sialyl-CD15. As a consequence of incubation with platelets, KMH-2 cells also produced increased amounts of tumor necrosis factors α (TNFα) followed by enhanced binding to human vascular endothelial cells (HUVEC). Incubation of both cell lines with activated platelets also induced activation of AP-1 transcription complex. Our findings are consistent with the concept that platelets play a critical role in the dissemination of HRS cells in HL, predominantly in the spleen, by increasing cell adhesion and thus promoting their proliferative and migratory properties beyond the lymphatic system.

Is classical Hodgkin's disease indeed a single entity?

We present a retrospective clinicopathological study on the significance of the histologic type of classical Hodgkin's disease (HD) in a cohort of patients from southern Israel. This was performed to critically evaluate the generally accepted view that classical HD is a single clinicopathological entity and the resultant impression that its segregation into four different histologic types remains essential only for the pathologist in his diagnostic endeavor. We confirmed the existence of a uniform response of nodular sclerosis (NS), and mixed cellularity-lymphocyte depletion (MC-LD)-HD to treatment, consideration being given to other classical prognostic factors. We also accept the fact that histological type is not a significant independent factor in terms of survival. Our findings, however, do suggest that NS-HD, on the one hand, and MC-LD-HD, on the other, are distinct biologic entities. Cases of NS differ significantly from those of MC-LD-HD with regard to sex and age distribution, and in the expression of several antigens and gene products, including sialylated-CD15, CD30, LMP1 and the p53 and mdm-2 gene products.

Over expression of interleukin-1alpha, interleukin-1beta and interleukin-1 receptor antagonist in testicular tissues from sexually immature mice as compared to adult mice.

The levels of IL-1alpha, IL-1beta and IL-1Ra were higher in homogenates of testicular tissue from sexually immature than those from mature mice. Immunohistochemical staining of testicular tissues from sexually immature and adult mice show that differentiated germ cells express higher levels of IL-1alpha compared to Sertoli cells and Leydig cells/interstitial cells. Peritubular cells of sexually immature and adult mice did not express IL-1alpha. Testicular tissue cells of adult mice showed high levels of expression of IL-1beta, mainly in the cytoplasm and nucleus of the spermatogonia and in spermatocytes. Sertoli cells and Leydig/interstitial cells were also highly stained for IL-1beta. However, peritubular cells did not express IL-1beta. On the other hand, testicular tissue cells from sexually immature mice, showed high levels of IL-1beta, mainly in spermatocytes. Spermatogonia showed low levels of IL-1beta expression. Also, high levels of IL-1beta expression were detected in Leydig/interstitial cells. Peritubular cells clearly showed IL-1beta expression. Testicular tissue cells from adult mice, showed IL-1Ra expression in spermatogonia, Sertoli and Leydig/interstitial cells. IL-1Ra expression was clearly present in the Golgi apparatus of spermatogonia and Sertoli cells. However, peritubular cells did not show IL-1Ra expression. Testicular tissue cells from sexually immature mice, also showed high levels of IL-1Ra expression mainly in the cytoplasm and nucleus of the spermatogonia and Sertoli cells. In addition, Leydig/interstitial cells and peritubular cells also expressed IL-1Ra. Our results demonstrate, for the first time, the expression of IL-1beta in germ and Sertoli cells, and IL-1Ra in Leydig/interstitial cells of testicular tissues from adult and sexually immature mice, under in vivo conditions. In addition, the relative elevated levels of the IL-1 system in the testis of immature mice compared to mature mice may indicate its involvement in the spermatogenesis.